1. Field of the Invention
This invention relates, in general, to application rollers and, in particular, to a new and useful application roller particularly for super-high speed coating of a sheet material.
As a coating method for treated liquid, such an application roller 23 made of a smooth felt 22 on its surface is known, as shown in FIGS. 6 and 7, wherein a treated liquid distributing pipe 20 extends through the center of the application roller and treated liquid distribution holes 21 are provided in the surface of the distributing pipe 20.
The application roller 23 rotates in contact with the surface of a continuously moving film or sheet, while the treated liquid flows into the felt 22 from the treated liquid distribution holes 21 and oozes out of the surface and is applied to the film or sheet.
This publicly known example is practical in the event that the film or sheet moves at a low speed.
However, it is known that, when the movement speed of this film exceeds 100 m/min., air moves between the surface of the application roller 23 and the film or sheet with subsequent splashing of the treated liquid and subsequent appearance of unevenness to the coated film.
Therefore, in the past, such a work has been performed as forming a coated film on the surface of film or sheet while moving the film or sheet at the speed not to cause any unevenness to the coated film.
As a result, there are some problems as follows in addition to low efficiency.
Usually, either in the case of a magnetic tape or in the case of a packaging film, the formation work of the coated film is performed within the same line. For this reason, since printing speed or bag making speed of a printer is, for example, usually at 100 m/min. or over, these speeds are reduced down to slower than 100 m/min. and therefore the productivity falls if the process for forming the coated film should be incorporated into the line.
Besides the method of forming a coated film on the surface of film or sheet, by atomizing the treated liquid and moving of the film or sheet within the atomized mist, or the method of spraying the treated liquid onto the surface of film or sheet is also publicly known.
However, even in case of these methods, there is a problem that the coated film becomes irregular in thickness if the moving speed becomes higher than 100 m/min.
The invention provides a roller capable of uniformly applying the treated liquid on the surface of film or sheet which moves at a super high speed, e.g. higher than 100 m/min.
In accordance with the invention, an application roller is provided with includes a central axial pipe or tubular member 2 having openings therein with a layer of non-woven cloth over the pipe through which the liquid may penetrate and an outer roller body having an exterior made substantially in a gear shape with circumferentially arranged top portions and valleys which includes an application material engaged over the surface of the gear-shaped exterior which is fed with the liquid which penetrates through the non-woven cloth material and close to a conveyor channel to the exterior of the gear-shaped roller body. In accordance with a feature of the invention, the valleys formed between the projecting gear piece formations permit the escape of any air going over the surface of the roller and move into the valleys during the revolution of the roller at very high speeds. The construction prevents the air from invading the space between the application material and the film or the sheet.
Accordingly, it is an object of the invention to provide an improved application roller which includes a hollow central portion with means for permitting the escape of a treated liquid from the central portion in radial and axial direction and onto the surface of the roller which is of a gear-shaped configuration to penetrate into an application material which is positioned at least at the tops of the gear piece-like formations.
A further object of the invention is to provide an application roller which is simple in design, rugged in construction and economical to manufacture.
The various features of novelty which characterize the invention are pointed with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects obtained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.